This invention is directed generally to electrical power monitoring and more particularly to a system and method for detecting high energy (e.g. voltage) transients in a power system.
High voltage transients can cause damage to power systems. The amount of damage depends on the amplitude and duration of the transient. This invention uses the Information Technologies Industries curve (ITIC) to analyze power system data in real time. Current products do this analysis off line because of the computationally intensive nature of the calculation. This invention runs in real time.
The calculation runs in real time and continuously compares incoming waveforms to all points on the ITI curve. Harmful transients are identified and differentiated from harmless transients.
The invention provides continuous, automatic monitoring of power systems for the purpose of detecting transients that may cause harm to equipment connected to the power system.
Briefly, in accordance with the foregoing, a method for detecting, in real time, high energy transients in an electrical power system, comprises obtaining real time data defining a power waveform, converting the data to digital data, calculating from the digital data a plurality of test point values, calculating incremental area values corresponding to differences between each adjacent pair of the plurality of test point values, an incremental time interval between adjacent the test point values being defined as a unit width of the area, such that the cumulative area under the waveform at a given testpoint is equal to the sum of the area calculated at that test point and the area, calculated at the previous test point, calculating the area of the waveform between adjacent pairs of test points by substracting the cumulative area at the later in time of the test points from the cumulative area at the earlier in time of the test points, and comparing each the area calculated under the waveform with an area at corresponding points in time on an ITI curve.
In accordance with another aspect of the invention, a method for detecting, in real time, high energy transients in an electrical power system, comprises obtaining real time data defining a power waveform, converting the real time data to digital form, converting the digital data to a unipolar absolute value, calculating a test point, determining a time intersect of the test point and an ITI curve, calculating an area corresponding to the test point and replacing the calculated area with the sum of the absolute value and an area at a prior test point, calculating an area of the waveform between a zero time intersect and an ITI curve time intersect with the test point, determining whether the waveform area is greater than or equal to a rectangular area under the ITI curve at the time intersect, if not, advancing to the next test point, if so, determining whether the data point at the time intersect is greater than or equal than the value of the ITI curve at the time intersect, and if not, advancing to the next data point, and if so, producing a trigger command.
In accordance with another aspect of the invention, a system for detecting, in real time, high energy transients in an electrical power system comprises means for obtaining real time data defining a power waveform, means for converting the data to digital data, means for calculating from the digital data a plurality of test point values, means for calculating incremental area values corresponding to differences between each adjacent pair of the plurality of test point values, the incremental time between adjacent the test point values being defined as a unit with of the area, such that the cumulative area under the waveform at a given test point is equal to the sum of the area calculated at that test point and the area, means for calculated at the previous test point, means for calculating the area of the waveform between adjacent pairs of test points by substracting the cumulative area at the later in time of the test points from the cumulative area at the earlier in time of the test points, and means for comparing each the area calculated under the waveform with an area at corresponding points in time on an ITI curve.
In accordance with another aspect of the invention, A system for detecting, in real time, high energy transients in an electrical power system comprises means for obtaining real time data defining a power wave form, means for converting the real time data to digital form, means for converting the digital data to a unipolar absolute value, means for calculating a test point, means for determining a time intersect of the test point and an ITI curve, means for calculating an area corresponding to the test point and replacing the calculated area with the sum of the absolute value and an area at a prior test point, means for calculating an area of the waveform between a zero time intersect and an ITI curve time intersect with the test point, means for determining whether the waveform area is greater than or equal to a rectangular area under the ITI curve at the time intersect, if not, advancing to the next test point, if so, determining whether the data point at the time intersect is greater than or equal than the value of the ITI curve at the time intersect, if not, advancing to the next data point, and if so, producing a trigger command.